Safety-fuse



J. J. RODNEY.

SAFETY FUSE.

APPLICATION FILED 0cm 25. 1919.

1 ,362,741 v Patented Dec. 21, 1920.

UNITED STATES JOHN J. RODNEY, OIE BROOKLYN, NEW YORK.

SAFE DY-FUSE.

Specification of Letters Patent.

Patented Dec; 21, 1920.

Application filed October 25, 1919. Serial No. 333,336.

fusible strip in a body of non-conducting.

material through the interstices of which the metal of the fusible link is adapted to be dispersed when fusion of the link or strip occurs and to inclose this body and the strip in an air tight protecting shell or casing of non-conducting material. In such fuses, especially the smaller ones, it is customary to employ a strip of flat fuse metal to which copper terminal wires are connected and in order to secure a good electrical connection between the parts the ends of theterminal members or wires are flattened out and are soldered to the fusible link at each end. After the link and terminal members have been assembled in the shell it is customary to solder the remaining ends of the terminal members to the metal caps on the ends of the shell. WVhen this latter soldering operation is performed it ofter occurs that the heat applied to the outer end of the terminal members for soldering is conducted through the terminal members and it causes the solder on the inner connections to fuse. This in many instances destroys or weakens the connections between the-terminal members and the links inside the shell where the defects are not visible. If such fuses are not all tested for conductivity they are not dependable whereas if they are all tested before they are sold many have to be discarded, resulting in loss. The object of my invention is to provide simple means for securing a good and dependable electrical contact between the fuse link and the terminals. In the form of the invention shown herein the connection is designed so that the parts will primarily grip each other while they are being soldered which expedites the work of soldering. Other advantages will be pointed out hereinafter.

In the drawing forming part of this application Figure l is a longitudinal section through a fuse embodying my invention in which view the solder has been omitted from one end of the link to show the pocket.

Fig. 2 is a perspective View of one of the terminal members, and

Fig. 3 is an edge view of a terminal member attached to the link preparatory to being soldered.

It is to be understood that the terminals are attached and soldered to the link before, these parts are assembled in the shell. In the drawing I have shown a shell 1 of non-conducting material, the shell being of cylindrical form and conforming to present practice, though any modification may be made in the shell. On each end of this shell there is a cap 2 having its edge 3 crimped to secure the cap to the shell and these caps are usually made of metal so that they may make electrical contact with the terminal members of the electric circuit. Within the shell and extending lengthwise thereof is the fusible member or link l. This may take any form but usually it consists of a flat strip of metal. At each end of the link there is connected a terminal member 5, usually of copper wire, and these terminal members extend through the central apertures 6 of the caps at opposite ends of the shell and their outer ends are generally soldered as at 7 to the caps to make an air tight closure and to secure a good electrical contact between the terminal members and the caps. The space within the shell is filled with a non-conducting filling material 8 such as is commonly used for such purpose.

-The present invention relates to the method of connecting the terminal members 5 and the link.

Each terminal member consists of a wire bent to form a loop or eye 9 and the wire is preferably returned to form adjacent ends 10 adapted to be attached to one of the caps. Before the parts are assembled in the shell the interior connections or those between the terminal members and the link are made as follows: A terminal member is attached to one end of the link by sliding the clip over one end of the link. The link enters between the loops 11 which normally lie close to each other, forcing these loop portions apart. The pressure developed between the link on the one hand and the loop portions 11 on the other is suficient to hold the terminal member and the link together while solder are:

is being supplied to the joint. This facilitates the handling of the device and the operator is less liable to oislodge the parts while applying the solder. Usually, the end of the link will not reach the extreme top of the loop 9 but there will be small space 12 between the top of this loop and the end of the link, which is an advantage, as will appear.

The next step is to apply the solder. A spot 13 of hot solder is placed in the space within the loop or eye 9 of the terminal member on one surface of the link and it is preferable to apply suiiicient solder to fill this space. if a flux is used and suflicient solder is applied, generally some of the solder will pass through the small space 12 and it will fill in the space within the loop 9 at the opposite side or surface of the link. When the Solder has set or cooled the connection will have been completed. T he same procedure is followed in attaching the other terminal member to the opposite end of the link. lVhen the connections have been completed the parts are assembled, together with the filler 8 in the tube and the ends of the terminal members are carried through the apertures 6 in the respective caps. Solder 7 is then applied to the ends 10 and the cap 2 around the aperture '6 to secure a good electrical connection between the terminal members and the caps. When the solder 7 is applied at the points of connection between the terminals and caps heat is more or less conducted through the terminal members until it reaches the solder 13 and in many instances the solder 18 is fused. In the ordinary fuse when this occurs the solder is displaced or spread and when it again cools, the joint between the terminal member and the link is weakened and sometimes broken altogether. The defect is not obvious as the parts are all inclosed. In the present device even if heat is conducted through the terminal member to such an extent as to fuse the solder at 13 this solder tends to remain in its original position since it is confined to a certain extent by the pocket formed by the loop 9 and the surface of the link. When the heat is removed the solder cools or sets again but it remains in its original position so that the connection returns to the same condition as before and it is in every way dependable. The clip action of the loop portions 11 holds the link and terminal member from displacement during the period that the solder 13 is fused, if at all, so that when this solder again sets the connection returns to its original condition.

Having described my invention, what I claim is:

1. A fuse including a fusible link and a terminal member connected'with said link, said terminal member having a portion adapted to form in connection with said link a pocket to prevent the spreading of fused solder and solder placed in said pocket for securing the link and terminal member together.

2. A fuse including a fusible link and a terminal member connected with said link, said terminal member having a portion constituting a clip portion adapted to grip the link, said clip portion being formed to constitute, in conjunction with said link, a pocket to prevent the spreading of fused solder and solder placed in said pocket for securing the link and terminal member together.

A fuse including a casing or shell havcaps on the ends thereof, a fusible link in said shell, terminal members connected witn said link and solder connecting the outer ends of said terminal members and said caps, said terminal members having a loop 9, and looped portions 11 adapted to press the link member between them, said loops forming, together with said link pockets on opposite surfaces of said link to prevent the spreading of fused solder, and solder placed in said pockets for securing the link and terminal members together.

Signed at the city, county and State of New York, this 23rd day of October, 1919.

JOHN J. ROONEY. 

